The objectives of this research project are: a) to develop a low-angle focusing diffractometer for use with the source of synchrotron radiation available at the Stanford Synchrotron Radiation Project, and to apply this resource to the study of systems of biological interest, and b) to apply the perturbed angular correlation of gamma radiation to studies of the dynamics of important biological processes. The low-angle diffractometer system has been applied to the study of retinal rod outer segment membranes, stimulated garfish olfactory nerve, and frog sciatic nerve. Additional experimental work will be carried out on the purple membrane, small lipid vesicles, and human heart muscle. The variable frequency feature of the synchrotron radiation source will also be used for the study of anomalous scattering effects in the low-angle X-ray diffraction from biological systems. Perturbed angular correlation of gamma radiation will be applied to studies of rabbit platelets, rabbit reticulocyte cell surface, the fate of liposomes in vivo, and heme catabolism.